This proposal describes experiments designed to examine the interaction of trace elements and susceptibility to infection in laboratory rats. Experimental zinc deficiency in rats and mice has a profound effect on the immune system however the relationship between the altered in vitro immune responses and host resistance to infection is unknown. We intend to examine the effect of dietary deficiency of two trace elements known to interact with one another (copper and zinc) on the ability of an animal to resist infectious challenge. Dietary levels of zinc and copper will be chosen to produce a marginal deficiency of these elements. The ability of rats fed these experimental diets to resist infection with S. typhimurium will be determined: a) in young adult animals maintained on the diet since weaning and b) progeny of mothers fed the experimental diets during gestation and lactation. In vitro tests of immune function will be carried out in those groups found to have a decreased or enhanced mortality rate as a result of alterations in the Zn/Cu dietary concentrations.